Thermostatic liquid fuel control device for furnaces



Sept. 20, 1966 J. D. WEBSTER THERMOSTATIC LIQUID FUEL CONTROL DEVICE FOR FURNACES Filed Sept. 25, 1964 INVENTOR JOHN D. WEBSTER Y I B j ATTO Y United States Patent C) 3,273,624 THERMOSTATIC LIQUID FUEL CONTROL DEVICE FOR FURNACES John D. Webster, Norfolk, Va., assignor of threetwentieths to Joseph M. Carson, Jr., and three-twentieths to Grover C. Gutland, both of Norfolk, Va.

Filed Sept. 25, 1964, Ser. No. 399,324 14 Claims. (Cl. 158-28) This application is a continuation-in-part of my copending application, Serial No. 244,689, led December 14, 1962, now abandoned.

The present invention relates generally to a control device for furnaces, and more particularly to a device for automatically cutting off the supply of liquid fuel to a furnace adapted to burn such fuel in the event that the furnace fire is inadvertently extinguished,

The desirability of providing a control device automatically actuable to cut off the flow of liquid fuel to a furnace in the event that the re in the furnace is unexpectedly extinguished, in order to prevent a dangerous accumulation of fuel in the fire-pot of the inoperative furnace, has long been recognized. Previously, those concerned with solving the problem of eliminating this type of lire hazard have principally relied upon such expedients as the provisions of elaborate control valves mounted in the furnace liquid fuel supply conduit which, upon the attainment of critical temperatures in the furnace, failure of the furnace damper to open, or failure of the furnace air supply, are actuated to cut olf the supply of liquid fuel to the furnace. Such devices, however, have generally been found to be complex and expensive, as well as relatively bulky and difcult to adapt to the fuel level control valve and tire-pot of the furnace.

The disadvantages of prior art devices such as those mentioned above are largely eliminated in the presently disclosed liquid fuel control device in which a minimum use of moving parts is made in the interest of simplicity and economy, and which is adapted for connection to the main liquid fuel supply line of many types of furnaces intermediate the fuel level control valve and fire-pot thereof. Modification of the fuel level control valve controls of a furnace to which the presently disclosed device is connected is seldom necessary, and, since the instantly disclosed control device operates in a liquid fuel bypass conduit and is actuated by means responsive to loss of heat from within the furnace, its utility is not affected by air locks in the main fuel supply line or in the fuel level control valve.

Accordingly, an object of the present invention is the provision of an inexpensive liquid fuel control device which is readily adapted for connection to liquid fuel fired furnaces.

Another object of the instant invention is to provide a liquid fuel control device for furnaces which is actuable independently of the furnace fuel level control valve.

According to the present invention, the foregoing and other objects are obtained by providing, in a furnace, a main liquid fuel supply line extending between the furnace fuel level control valve and the furnace lire-pot section in which a conventional feeder valve is mounted. Further, a dispenser valve is mounted adjacent the furnace in a liquid fuel bypass conduit; one end of which is connected to the main liquid fuel supply line between the furnace fuel level control valve and the feeder valve, and the other end of which is connected to the main liquid fuel supply line between the feeder valve and the furnace fire-pot section. A bi-metallic actuator plate iiexionally distortable in response to the increase or decrease of heat within the furnace is mounted atop the furnace, and a cable passing over suitable pulleys or sheaves connects the actuator plate to the dispenser valve.

Upon ignition of the furnace, liquid fuel is introduced into the furnace fire-pot section through the main liquid fuel supply line and the feeder valve mounted therein. As the furnace grows hotter, distortion of the actuator plate takes place in response to the increase of heat within the furnace, drawing the entire length of the cable connected thereto in the direction of the actuator plate with the result that the dispenser valve is opened. The feeder valve is then manually or otherwise closed to prevent the flow of liquid fuel into the furnace fire-pot section except through the liquid fuel bypass conduit and the dispenser valve, which will continue as long as the re burns in the furnace fire-pot section. In the event that the furnace fire is inadvertently extinguished, the actuator plate returns to its undistorted configuration in response to the decrease of heat within the furnace, permitting a cornpression spring within the dispenser valve to urge the valve to closed position as the cable moves in reverse direction, immediately cutting off the supply of liquid fuel to the furnace fire-pot section and eliminating a dangerous lire hazard.

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing where- 1n:

FIG. l is a perspective view of a furnace incorporating the liquid fuel control device; and,

FIG. 2 is a vertical cross-sectional view of the dispenser valve mounted in the liquid fuel bypass conduit.

Referring now more particularly to the drawing, wherein like reference numerals designate identical parts throughout the several views, and more specifically to FIG. l, there is shown a furnace, generally designated by the reference numeral 11, indicated as having a lower fire-pot section 12, an upper furnace top section 13, and a flue 14 extending outwardly from furnace top 13. A fuel level control valve 15 is mounted on furnace 11 near the lower extremity thereof adjacent fire-pot section 12; the fuel level control valve 15 being connected by fuel supply line 16 to a suitable fuel supply reservoir, not illustrated. A main liquid fuel supply conduit 17 is connected at one end to fuel level control valve 15; the other end thereof extending towards lire-pot section 12. Main liquid fuel supply conduit 17 includes a Y-connection 18 or the like, and further includes a conventional main feeder valve 19 mounted therein at a point more remote from fuel level control valve 15 than the Y-connection 18. The end of main liquid fuel supply conduit 17 extending towards fire-pot section 12 is connected through the medium of a T-connection 21 or the like to a nozzle for introducing liquid fuel into fire-pot section 12 disposed adjacent to and extending through the fire-pot sec- Ation entry port 22; the T-connection 21 further including a manually or otherwise operable control pin 23 extending therethrough and into the nozzle extending through lire-pot section 12 entry port 22.

A liquid fuel bypass conduit 24 is connected at one of its ends into main liquid fuel supply conduit 17 at the hereinbefore mentioned Y-connection 18, which was provided for this purpose, and is `connected at the other of its ends through the medium of a T-connection 25 or the like to the nozzle extending through entry port 22. A dispenser valve, generally designated by the reference numeral 26, is mounted in liquid fuel bypass conduit 24 intermediate the ends thereof; dispenser valve 26 further being mounted adjacent furnace 11.

Turning now to FIG. 2 of the drawing, it will readily be seen that dispenser valve 26 includes a closed cylindrical housing 27 through which fuel exit and entry ports 28 and 29, respectively, are formed; the connections of liquid fuel bypass conduit 24 to dispenser valve 26 being made around ports 28 and 29. A hollow piston or plunger 31 is mounted for vertical reciprocal sliding movement within cylindrical housing 27; plunger 31 being constituted by a horizontal circular plate only slightly smaller in diameter than the inner cylindrical wall of housing 27, and by a cylindrical skirt depending from the horizontal plate and in substantial contact with the inner cylindrical wall of housing 27. As plunger 31 descends toward the lower extremity of housing 27 to close dispenser valve 26 by blocking the fuel exit port 28, the hollow interior thereof, by compressing the air within housing 27 underlying plunger 31, provides a dashpot cushioning effect. A wire or other rigid support member 32 extends upwardly from plunger 31 through the top of housing 27. Further, a helical compression spring 33 is positioned about member 32; the ends thereof pressing against the top wall of housing 27 and a horizontal plate 34 attached to member 32 within housing 27. It will now be apparent that dispenser valve 26 is normally maintained in a closed position through the action of the helical spring 33.

Returning now to further `consideration of FIG. 1 of the drawing, it will be seen that a metallic box like enclosure 35 is positioned atop the furnace 11; a portion of enclosure 35 having been broken away in the drawing to show the interior thereof. It will be noted, however, that enclosure 35 may just as readily be mounted on one of the sides of furnace 11, if deemed desirable. A plurality of pins 36 extending through the side walls of enclosure 35 support horizontally therewithin and spaced from furnace 11 a bi-metallic or other heat responsive flexible actuator plate 37, such as the type of bi-metallic plate commercially available under the Truflex trademark. The actuator plate 37, if the above mentioned bimetallic material is used, is arranged with the metallic layer thereof having the higher coefficient of thermal expansion adjacent furnace 11. The enclosure 35, support pins 36, and actuator plate 37 may collectively be referred to as, or termed, a heat responsive dispenser valve actuator. A cable 38 attached to actuator plate 37 extends upwardly through the upper wall of enclosure 35, thence over pulleys or sheaves 39 and 41, and then downwardly where it is connected to support member 32 of dispenser valve 26.

Upon ignition of furnace 11, liquid fuel is introduced into furnace fire-pot section 12 through main liquid fuel supply conduit 17 and the feeder valve 19 mounted therein. As furnace 11 grows hotter, actuator plate 37 bows inwardly toward furnace 11, as indicated in FIG. l, in response to the increase of heat within the furnace 11, drawing the entire length of cable 38 in the direction of the bow of actuator plate 37. As a result, dispenser valve 26 is opened. Feeder valve 19 is then manually or otherwise closed to prevent the flow of liquid fuel into the re-pot section 12 except through the liquid fuel bypass conduit 24 and dispenser valve 26, which will continue as long as the fire burns in furnace 11. If it happens that the furnace re is unexpectedly extinguished, actuator plate 37 returns to its unbowed configuration as furnace 11 cools, permitting dispenser valve 26 to close under the action of helical compression spring 33, cutting off the flow of liquid fuel to fire-pot section 12 of furnace 11 to eliminate a dangerous fire hazard.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A liquid fuel control device connectible to a furnace of the type having a fuel supply main conduit interconnecting a supply of fuel and said furnace and having a feeder valve mounted in said fuel supply main conduit, comprising:

(A) a bypass conduit having its respective ends adapted to be connected to said main conduit before and after said feeder valve;

(B) a dispenser valve mounted in said bypass conduit, said dispenser valve including a spring actuated plunger movable between a position obstructing the flow of fuel through said bypass conduit to a position permitting the flow of fuel through said bypass conduit, said spring urging said plunger into said position obstructing the flow of fuel through said bypass conduit; and

(C) a heat-responsive dispenser valve actuator, including a metallic plate adapted to be supported upon said furnace and -connected to said dispenser valve plunger via cable means, said plunger being movable against the action of said spring to said position permitting the flow of fuel through said bypass conduit as said metallic plate flexes in response to firing of said furnace.

2. A liquid fuel` control device as in claim 1, including means for closing said feeder valve.

3. A liquid fuel control device connectible to a liquid fuel red furnace of the type having a fire-pot section, a main liquid fuel supply conduit extending from a supply of fuel towards said fire-pot section, and a main feeder valve mounted in said main liquid fuel supply conduit; said liquid fuel control device comprising:

(A) a liquid fuel bypass conduit having a first end adapted for connection to said main liquid fuel supply conduit on one side of said feeder valve and having a second end adapted for connection to said main liquid fuel supply conduit on the other side of said feeder valve;

(B) a dispenser valve mounted in said liquid fuel bypass conduit, said dispenser valve including a housing having an elongated side wall and a pair of end walls enclosing a volume of space through a portion of which liquid fuel flowing in said liquid fuel bypass conduit must pass, a piston-like plunger mounted for reciprocal sliding Imovement within said housing, resilient means for maintaining said plunger in a position to block the flow of liquid fuel through said housing and thereby keep said dispenser valve closed, and an elongated member having a first end connected to said plunger and having a second end extending exteriorly of said housing through one of said end walls to which a tensile force may be substantially linearly applied for overriding the action of said resilient means and moving said plunger out of said position in which it blocks the flow of liquid fuel through said housing thereby opening said dispenser valve for so long as said tensile force is maintained; and,

(C) a heat-responsive dispenser valve actuator adapted to be mounted upon said furnace and operatively coupled to said dispenser valve, said actuator including a metallic plate adapted to be supported adjacent said furnace to which is connected a first end of a cable having a second end connected to said dispenser valve elongated member, said metallic plate being readily bendable towards said furnace upon the increase of heat therewithin for transmitting a tensile force through said cable for substantially linear application to said dispenser valve elongated member.

4. The liquid fuel control device according to claim 3, including means for closing said feeder valve.

5. The liquid fuel control device according to claim 3, wherein said actuator plate is composed of two layers of metal differing in composition, the metallic layer thereof having the higher coefficient of thermal expansion being disposed adjacent said furnace.

6. The liquid fuel control device according to claim 3, wherein said resilient means includes a compression spring disposed about said elongated member within said housing, said compression spring having a first end pressing against an end wall of said housing and having a second end operatively coupled with said plunger.

7. The liquid fuel control device according to claim 6, wherein said actuator plate is composed of two layers of metal differing in composition, the metallic layer thereof having the higher coefficient of thermal expansion being disposed adjacent said furnace.

8. The liquid fuel control device according to claim 7, including means for closing said feeder valve.

9. A liquid fuel fired furnace having a fire-pot section, a main liquid fuel supply conduit extending from a supply of fuel towards said fire-pot section, a main feeder valve mounted in said main liquid fuel supply conduit, and a liquid fuel control device; said liquid fuel control device comprising:

(A) a liquid fuel bypass conduit having a first end connected to said main liquid fuel supply conduit on one side of said :feeder valve and having a second end connected to said main liquid fuel supply conduit on the other side of said feeder valve;

(B) a dispenser valve mounted in said liquid fuel bypass conduit, said dispenser valve including a housing having an elongated side wall and a pair of end walls enclosing a volume of space through a portion of which liquid yfuel flowing in said liquid fuel bypass conduit must pass, a piston-like plunger mounted for reciprocal sliding movement within said housing, resilient means `for maintaining said plunger in a position to block the ow of liquid fuel through said housing and thereby keep said dispenser valve closed, and an elongated member having a first end connected to said plunger and having a second end extending exteriorly of said housing through one of said end walls to which a tensile force may be substantially linearly applied for overriding the action of said resilient means and moving said plunger out of said position in which it blocks the llow of liquid fuel through said housing thereby opening said dispenser valve for so long as said tensile force is maintained; and,

(C) a heat-responsive dispenser valve actuator mounted upon said furnace and operatively coupled to said dispenser valve, said actuator including a metallic plate supported adjacent said furnace to which is connected a first end of a cable having a second end connected to said dispenser valve elongated member, said metallic plate being readily bendable towards said furnace upon the increase of heat therewithin for transmitting a tensile force through said cable for substantially linear application to said dispenser valve elongated member.

10. The furnace according to claim 9, including means for closing said feeder ivalve.

11. The `furnace according to claim 9, wherein said actuator plate is composed of two layers of different metals, the metallic layer thereof having the higher coefficient of thermal expansion `being disposed adjacent said furnace.

12. The furnace according to claim 9, wherein said resilient means includes a compression spring disposed about said elongated member within said housing, said compression spring having a first end pressing against an end wall of said housing and having a second end operatively coupled with said plunger.

13. The furnace according to claim 12, wherein said actuator plate is composed of two layers of different metals, the metallic layer thereof having the higher coeiicient of thermal expansion being disposed adjacent said furnace.

14. The furnace according to claim 13, including means for closing said feeder valve.

References Cited by the Examiner UNITED STATES PATENTS 812,715 2/ 1906 Asheraft 158-28 1,624,039 4/ 1927 Dana 236-16 1,703,803 2/ 1929 Widstrom 236-19 X 1,824,057 9/ 1931 Robertshaw et al. 236-80 2,101,393 12/1937 Herbster 158-139 2,326,734 8/ 1943 Little.

2,346,813 4/ 1944 yBreese 15 8-42.4 X

ALDEN D. STEWART, Primary Examiner. 

1. A LIQUID FUEL CONTROL DEVICE CONNECTIBLE TO A FURNACE OF THE TYPE HAVING A FUEL SUPPLY MAIN CONDUIT INTERCONNECTING A SUPPLY OF FUEL AND SAID FURNACE AND HAVING A FEEDER VALVE MOUNTED IN SAID FEED SUPPLY MAIN CONDUIT, COMPRISING: (A) A BYPASS CONDUIT HAVING ITS RESPECTIVE ENDS ADAPTED TO BE CONNECTED TO SAID MAIN CONDUIT BEFORE AND AFTER SAID FEEDER VALVE; (B) A DISPENSER VALVE MOUNTED IN SAID BYPASS CONDUIT, SAID DISPENSER VALVE INCLUDING A SPRING ACTUATED PLUNGER MOVABLE BETWEEN A POSITION OBSTRUCTING THE FLOW OF FUEL THROUGH SAID BYPASS CONDUIT TO A POSITION PERMITTING THE FLOW OF FUEL THROUGH SAID BYPASS CONDUIT, SAID SPRING URGING SAID PLUNGER INTO SAID POSITION OBSTRUCTING THE FLOW OF FUEL THROUGH SAID BYPASS CONDUIT; AND (C) A HEAT-RESPONSIVE DISPENSER VALVE ACTUATOR, INCLUDING A METALLIC PLATE ADAPTED TO BE SUPPORTED UPON SAID FURNACE AND CONNECTED TO SAID DISPENSER VALVE PLUNGER VIA CABLE MEANS, SAID PLUNGER BEING MOVABLE 